摘要
为研究土工格栅加筋橡胶碎石混合料的力学特性与变形控制作用机理,基于大尺寸三轴试验,分析3种橡胶掺量碎石混合料在不同加筋形式下的应力-应变关系曲线、体变-轴向应变关系曲线,研究土工格栅竖向间距、筋材层数对其力学响应与变形特性的影响规律,并对试验结果进行拟合分析。研究结果表明,合理的土工格栅布置形式能有效提升橡胶碎石混合料峰值应力并抑制其发生剪胀变形。试验中5种双层加筋的最优竖向间距为d=150 mm。土工格栅的加筋效果在达到一定轴向应变后才能得以体现,且随着试样中橡胶掺量的增加,此轴向应变值逐渐增大。3种橡胶掺量碎石混合料均随着土工格栅加筋层数的增多,加筋效果显著提升,同时加筋层数相同的试样,其剪切破坏形态基本一致。随着橡胶掺量的增加,试样的剪切破坏模式由应变软化型逐渐过渡为应变硬化型,同时土工格栅的加入也增加了试样的延性。基于邓肯-张双曲线模型,增加拟合参数ψ,修正了能够描述橡胶碎石混合料的应力-应变特征的预测公式,并验证了该公式的合理性。研究成果可为橡胶碎石混合料的实际应用提供一定的理论基础。
In order to study the mechanical behavior and deformation control mechanism of geogrid reinforced rubber gravel mixtures,the stress-strain relationship and volumetric strain-axial strain relationship curves of three kinds of rubber gravel mixtures under different reinforcement forms were analyzed based on large-scale triaxial tests.The influence of the vertical spacing of geogrids and the numbers of geogrid reinforcement layers on its mechanical response and deformation characteristics were investigated,and the test results were fitted.The research results showed that a reasonable geogrid arrangement can effectively increase the peak stress of the rubber gravel mixture and restrain its shear dilatancy deformation.The optimal vertical spacing of the five doublelayer reinforcements in this study was d=150 mm.The reinforcement effect of the geogrid can be mobilized after reaching a certain axial strain.As the rubber contents increase in the specimens,the axial strain value gradually increases.As the geogrid reinforcement layers increase,the reinforcement effect of three kinds of rubber gravel mixture is significantly improved.Moreover,the shear failure modes of the specimens with the same reinforcement layers are basically the same.With increasing rubber contents,the shear failure mode of the specimens gradually transitioned from strain softening type to strain hardening type.The geogrids also increase the ductility of the specimens.Based on the Duncan-Chang hyperbolic model,the fitting parameterψis added to improve the prediction formula that could reasonably describe the stress-strain characteristics of the rubber gravel mixtures.The formula is verified by the experimental data obtained in this study.The research results can provide a certain theoretical basis for the practical application of rubber gravel mixtures.
作者
王志杰
蔡永明
齐逸飞
杨广庆
叶朝良
WANG Zhijie;CAI Yongming;QI Yifei;YANG Guangqing;YE Chaoliang(State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;Key Laboratory of Roads and Railway Engineering Safety Control,Ministry of Education,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;School of Civil Engineering,Shijiazhuang Tiedao University,Shijiazhuang 050043,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2023年第7期2509-2520,共12页
Journal of Railway Science and Engineering
基金
国家自然科学基金资助项目(51709175)
河北省高等学校科学技术研究项目(BJ2020045)
石家庄铁道大学硕士研究生创新项目(YC2022008)。
关键词
土工格栅
橡胶碎石混合料
筋材竖向间距
加筋层数
应力-应变关系
geogrid
rubber gravel mixture
vertical spacing of reinforcement
number of reinforcement layers
stress-strain relationship
作者简介
通信作者:杨广庆(1971-),男,河北沧州人,教授,博士,从事土工合成材料加筋路基方面的研究,E-mail:yanggq@stdu.edu.cn。
